Writing implement



April 30, 1968 G. 1.. WILCOX 3,380,152

WRITING IMPLEMENT Filed Oct. 18, 1965 M4 cw/us Pee/ 426 Worse BIA/s5 P4 4 rs We Tee Elms:

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A/ou- Cououcrlve Aid/0 1 BY PM, W M5627 6% i WM United States Patent 3,380,152 WRITING IMPLEMENT Gary L. Wilcox, Fort Madison, Iowa, assignor, by mesne assignments, to Textron, Inc., Providence, R.I., a corporation of Rhode Island Filed Oct. 18, 1965, Ser. No. 497,077 Claims. (Cl. 29-527) This invention relates to a writing implement and more particularly to a method of manufacturing an improved writing assembly of the type employing a rotatable ball.

In many instances, it is desirable to plate the exterior surface of a ball point writing tip assembly not only for protection against corrosion, wear and damage, but to improve the appearance of the tip and permit a color match with other metal parts used on a 'ball point pen. Prior to the present invention, however, plating of a ball point tip has been so costly that comparatively few commercially produced tips have had the advantage of a protective and decorative plate.

While stainless steel has been adopted recently by some manufacturers for use in making a ball point tip, the cost of processing this material is quite high and most tips are still being made of a copper alloy, such as brass or bronze. Such alloys, while they have been used for a number of years, do have certain drawbacks. For instance, they are relatively soft and a tip made of this type of material will be worn and/ or otherwise damaged quite readily should it be dragged over an abrasive surface, such as paper. Also, in many cases, such tips will discolor and corrode gradually when exposed to atmospheric conditions.

The prior art teaches the plating of a ball point tip before insertion of the ball and closure of the lip. However, these prior processes result in substantially increased manufacturing costs because of the necessity of interrupting the normal processing sequence of the tip for the plating operation before insertion of the ball and closing of the lip. With present-day equipment, the tip blank normally is retained in the same chuck throughout its complete manufacture, including ball insertion and lip closing, and if removed for a special intermediate operation, such as plating, it must then be rechucked with an attendant loss of time and likelihood of misalignment during subsequent assembly and finishingoperations.

The present invention eliminates the problems which have been encountered in prior efforts to provide an externally plated writing tip.

Accordingly, one object of this invention is the provision of an improved method of plating the tip of a ball type ink dispensing implement.

Another object of this invention is the provision of an inexpensive ball point tip plating method wherein the plating'is accomplished after the tip has been completely assembled.

Yet a further object of this invention is to provide a method wherein a completed ball point Writing tip can be plated and stored for normal periods without concern as to galvanic corrosion or undesirable concentration of plating salts in the ball socket during such storage.

In one method provided by the present invention, a tip, made of a copper alloy having an electrochemically active surface and carrying an electrochemically passive stainless steel ball, is given a nickel plate of about .5 to .7 micron in thickness, the tip assembly subsequently being cleaned as thoroughly as possible and stored in a non-corrosive fluid which is miscible with ball point ink and effective to prevent galvanic corrosion or formation of salt crystals within the socket as a result of any residual plating bath material left therein.

A complete understanding of this invention will be obtained from the following detailed description when taken with the accompanying drawings, in which:

FIGURE 1 is an enlarged longitudinal sectional view of the forward end of a writing assembly plated in accordance with the present invention; and

FIGURE 2 is a diagram or flow chart illustrating the several steps involved in the method of manufacturing the embodiment of FIGURE 1.

The forward end of a typical ball point writing assembly 10 is illustrated in FIGURE 1, this assembly including a body portion or tip 11 machined from the usual brass or bronze alloy.

As will be understood in the art, the tip 11 includes in its forward end a socket 12 communicating with a reduced ink passageway 14 through which ink is fed from a reservoir (not shown) of the usual type. The generally frusto-conical base of the socket 12 is provided with a plurality of seats 16 which are, disposed radially in a spaced relationship with one another to provide therebetween a number of ink passages 17 for movement of ink from the ink passageway 14 around the ball and into the small annular ink reservoir space 18. From this space 18, ink is metered on to the surface of the ball in a thin film as the ball rolls over a writing surface to deposit a visible trace.

As indicated previously, tips of this type are subject to various deteriorating influences. For instance, under certain atmospheric conditions, particularly if stored for a comparatively long period of time, the exterior surface will become discolored, giving an unsatisfactory appearance. Also, particularly in the lip area 20 where the metal of the tip has been spun to a very thin edge, there is danger of damage as a result of contact with an abrasive surface, such as paper. Further, in other instances, for aesthetic reasons, a manufacturer may want to provide a writing tip which is of a color other than the natural color of the usual bronze or brass.

Heretofore, the solution to these various problems has not been attainable on an inexpensive mass production basis because of the necessity of withdrawing the incomplete tip from the manufacturing process for the addition of the plate prior to insertion of the ball and closure of the tip. With the present invention, however, a manufacturer can plate the Writing assembly after it has been finished, thereby completely eliminating any disruption of the manufacturing process while at the same time depositing plate only where it is needed-on the exterior of the tip.

These advantages are accomplished by a new and unique plating method which is not only inexpensive and simple, but which will provide an adequate protective coating for the tip.

The first step in this process consists of finishing the tip 11 with the necessary socket 12, ink passageway 14 and other usual elements such as the base seats 16 and ink channels 17. As indicated heretofore, this tip may be machined from any one of the usual materials used for the purpose, such as brass or bronze, so long as it is a good conductor of electricity and has or can be treated to provide an electrochemically active exterior surface 22.

The ball 24 is substantially the same in diameter as the interior of the socket 12 and is held snugly in the socket after the lip 20 has been spun therearound in the usual manner.

The ball of the present invention may be any one of several different materials, as will be discussed in more detail herebelow. However, in the present embodiment, the ball preferably is formed of stainless steel which, in its normal state, will provide an electrochemically passive surface. Stainless steel can be treated to create an electrochemically active surface, but as employed in the present invention, it should not be so treated for reasons which will become obvious from the following discussion.

After the assembly has been completed, it normally would have traces of cutting oil, etc., present on its surfaces. This oil should be removed using a degreasing process which includes a solvent, detergent or other cleaner which is non-reactive and non-corrosive insofar as the ball 24 is concerned so as not to change the electrochemical passivity of its surface. One suitable degreasing material is trichloroethylene, into which the finished assembly 10 is first dipped and agitated, and then allowed to drip in an environment saturated with vapor of the trichloroethylene in order to insure that all traces of oil are removed.

After this degreasing process has been completed, the assembly 10 should then be rinsed thoroughly in distilled water to remove any residual traces of the cleaning material.

The chemically clean, electrochemically active exterior surface of the tip is then plated. Generally, for economy in this step, a comparatively large number of such assemblies are plated at one time in a standard plating barrel or basket which is adapted to create continuous movement or agitation of the tips during the plating process to insure a uniform plate deposit over their entire exterior surfaces.

In the embodiment being described, the plating 26 preferably is of a bright nickel, being deposited from an aqueous Watts type nickel bath containing a brightener. As will be understood, the brightener will eliminate any need for subsequent polishing or buffing the plated tip to provide therein an aesthetic pleasing appearance.

The plating step is critical in the present method as the thickness of the plate must be controlled carefully to prevent undesirable build-up of material around the lip and consequent freezing of the ball 24. After a number of tests, it was found that with the usualwriting tip, the plate thickness on the exterior of the lip 20 should range from a minimum of about .25 micron to a maximum of about .8 micron. If the plate is less than about .25 micron it does not give adequate protection, and if it is thicker than about .8 micron on the external forward end of the lip 20 the minute amount of thaw 27 of plate on the interior of the lip 20 may build up sulficiently either to freeze or at least interfere with free rotation of the ball 24. Preferably, the plate should measure from about .5 to about .75 micron in thickness. In the present embodiment, it has been found that this range of thickness will be realized by using a current of about 20 amperes for about 2 minutes.

It will be understood, of course, that the actual plate thickness for a particular tip assembly will depend to a great extent upon the tightness of the lip around the ball prior to the plating step. Some tip assemblies are spun to provide what is considered an open lip, and in such assemblies the plate thickness might be permitted to range up to 1 micron before it will interfere with proper rotation of the ball 24. On the other hand, with a tight lip the plating may have to be held to about .5 micron or less, as determined readily by a few simple laboratory plating tests on the type of assembly to be treated by the method herein discussed.

During the plating step, the ball 24 will remain free of deposit because of the electrochemically passive nature of its exterior surface.

Following the plating step, the tip assembly or assemblies are removed from the plating bath and promptly rinsed to remove as much of the residue of the plating bath as possible. This rinse, started before the plate bath residue has dried, should be thorough, preferably consisting of three or four rinses in distilled water which is not only boiling, but agitated ultrasonically by an ultrasonic agitating device.

At this point, the plating and initial cleaning steps are complete. However, it has been found that a minute amount of the plating solution will remain in the very fine capillary spaces between the ball 24 and the interior surface of the socket 12. Being a good electrical conductor, this aqueous plating solution, if permitted to remain in the socket cavity, will cause the passage of electrical current between the dissimilar metals of the ball and tip and this current will result in galvanic corrosion on the stainless steel ball 24. This corrosion may progress far enough before evaporation of the water from the solution, to cause freezing of the ball within the socket. Even if corrosion should not occur, as with a non-metallic ball, it has been experienced that ball freeze may occur in certain instances solely as a result of formation of nickel salt crystals within the ball socket as the aqueous vehicle evaporates from the residual plating solution.

To overcome these problems, the present method includes the further step of rinsing the tip assembly 10, promptly following the water rinses in a substantially non-conductive solvent type liquid which is anhydrous but miscible with water. This anhydrous liquid serves to extract or absorb any water remaining in the tip cavities thereby preventing the occurrence of any significant galvanic corrosion on the stainless steel ball 24. It has been found that a four minute rinse of the tip assembly 10 in methyl alcohol, with suitable agitation, will satisfactorily extract or absorb substantially all of the water in the assembly.

Even at this point, however, a residual amount of dissolved nickel plating bath salts will remain in the tip cavity, and for this reason it is necessary to maintain fluid in the tip to prevent concentration of these salts as crystals. This is accomplished by storing the tip assembly 10 until it is ready to be filled with ink in a second solvent, such as acetone, which is substantially non-conductive and miscible both with first anhydrous liquid rinse material and the ink intended for use with the tip. Such storage can be accomplished easily merely by putting a quantity of the finished tip assemblies in a jar or container and then filling it with acetone. Before this storage step, it may be desirable to rinse the assembly in acetone to remove as much of the methyl alcohol as possible.

From the preceding description, it will be understood that the tip assembly 10 should be held in the storage fluid until just before it is to be assembled with a reservoir and filled with ink. Thus, the manufacturer should take reasonable precautions to insure prompt handling and filling after removal of the tip assembly from the storage fluid.

Any acetone remaining within the tip prior to the ink filling operation will, of course, dissipate into the ink since it is miscible therewith. Also, because of the presence of ink within the socket subsequent to the filling operation, any minute amount of residue plating salts remaining therein will be maintained in a dissolved condition and incapable of interfernece with subsequent performance of the writing assembly.

It will be understood by those in the art that other materials may be used in the present invention. For instance, some manufacturers may prefer to use a sintered carbide ball in place of the stainless steel ball 24. In this event, the sintered carbide ball would present an electrochemically active exterior surface on which suflicient plating would be built up to cause freezing of the ball. Thus, if a ball having an externally active electrochemical surface is chosen, it should be treated or coated to make this surface passive. For example, it could be dipped in a thin lacquer and permitted to dry before being assembled with the tip. And in this event, the material used in the degreasing step should be selected so that it does not affect the electrochemically passive nature of the applied coating.

The coating thus put on the ball would not interfere with performance of the tip assembly 10 since it is quickly Worn away.

Another example of a ball material admirably suited for use in the method for this invention is a stone ball such as the synthetic sapphire used by certain manufacturers. Such a ball would present a natural electrochemically passive surface and no further treatment would be required thereon.

Further, it should be pointed out that materials other than nickel can be used for the protective or decorative plate 26. Examples of other plating materials would include gold, silver, chrome and the like. The critical factor, of course, is that the thickness of the plate be controlled very closely and not go beyond the point of interfering with free rotation of the ball 24.

It will be understood that the present invention is not to be limited to the materials and steps described above. Numerous other arrangements may be devised readily by those skilled in the art which will embody the principals of and fall within the spirit and scope of this invention.

I claim: 1

1. The method of making a ball type ink dispensing implement which consists of forming a socket in a metallic tip having an electrochemically active exterior surface, preparing a ball having an electrochemically passive surface, confining said ball within said socket with a portion thereof exposed for free universal rotation, immersing said assembly in a plating bath, depositing on said tip a thin metallic coating, removing said assembly from said bath, promptly rinsing said assembly to remove residual material from said plating bath, and thereafter maintaining said assembly in a non-conductive fluid until ready for inking.

2. The method of making a ball type ink dispensing implement which consists of forming ink channels and a socket in a metallic tip having an electrochemically active exterior surface, preparing a writing ball having an electrochemically passive surface, confining a major portion of said ball within said socket for free universal rotation with a portion thereof exposed, degreasing said assembled tip and ball with a noncorrosive cleaner, immersing said assembled tip and ball in a plating bath, depositing on said tip a metallic plate ranging between about .25 micron to about .8 micron in thickness, removing said assembly from said 'bath, promptly rinsing said assembly in water, and immersing said assembly in a nonconductive fluid Where it may be stored ready for inking.

3. A method for finishing and storing a ball point pen writing tip assembly including an apertured ink conducting metallic tip with an electrochemically active exterior surface and a ball confined within the tip for free universal rotation with a portion thereof exposed, the ball having an electrochemically passive surface; said method comprising the steps of immersing the assembly in a plating bath, electrodepositing a metallic coating ranging from about 0.25 to about 0.8 micron in thickness onto said tip while the tip is immersed in the bath, removing the assembly from the bath, promptly rinsing the assembly and immersing the assembly in a non-conductive ink miscible fluid where it may be stored until ready for inking.

4. The method of making a ball type ink dispensing implement which consists of forming ink channels and a socket in a metallic tip having an electrochemically active exterior surface, preparing a writing ball consisting of a metal other than the metal of said tip and having an electrochemically passive surface, confining a major portion of said ball within said socket with a portion thereof exposed for free universal rotation, degreasing said assembled tip and ball with a non-corrosive cleaner, immersing said assembly in a plating bath containing a salt of a metal other than the metals of said tip and ball, depositing on said tip a metallic coating ranging between about .25 micron to about .8 micron in thickness, removing said assembly from said bath, promptly rinsing said assembly in water to remove residual plating salts,

rinsing said assembly in an anhydrous liquid which is miscible with water, storing said assembly in a non-conductive ink miscible fluid, and filling said assembly with ink.

5. The method of making a ball type ink dispensing implement which consists of forming ink channels and a socket in a metallic tip having an electrochemically active surface, preparing a writing ball consisting of a metal other than the metal of said tip and having an electrochemically passive surface, confining a major portion of said ball within said socket for free universal rotation therein, degreasing said assembled tip and ball with a non-corrosive solvent cleaner, immersing said assembled tip and ball in a plating bath containing a salt of metal other than the metals of said tip and said ball, depositing on said tip a metallic plate, stopping said de posit after said plate has reached a thickness ranging between about .25 micron to about .8 micron, removing said assembly from said bath, promptly rinsing said assembly in water to remove residual plating salts, promptly rinsing said assembly in an anhydrous liquid which is miscible with water, and maintaining said assembly in a moistened condition until ready to be filled with ink by storage thereof in a non-conductive fluid which is miscible with said liquid and with said ink.

6. The method of making a ball type ink dispensing implement which consists of forming ink channels and a socket in a metallic tip having an electrochemically active exterior surface, preparing a writing ball consisting of a metal other than the metal of said tip and having an electrochemically passive surface, confining a major portion of said ball Within said socket with a portion thereof exposed for free universal rotation, degreasing said assembled tip and ball with a non-corrosive solvent cleaner, rinsing said assembly to remove residual cleaner, im mersing said assembly in a plating bath containing a salt of a metal other than the metals of said tip and said ball, depositing on the exterior surface of said tip a metallic plate, stopping said deposit after said plate has reached a thickness ranging between about .4 micron and about .75 micron, removing said assembly from said bath, promptly rinsing said assembly in boiling water to remove residue of said bath, promptly immersing said assembly in a water miscible liquid for extracting residual water therefrom, storing said assembly in a non-conductive fluid which is miscible with said liquid, and filling said assembly with an ink which is miscible with said fliud.

7. The method of making a ball type ink dispensing implement which consists of preparing a tip blank of an electrochemically active copper base alloy, forming ink channels and a socket in said tip blank, preparing a stainless steel writing ball having an electrochemically passive surface, inserting said ball into said socket with a portion thereof exposed, constricting the outer end of said tip to confine said ball within said socket for free universal rotation therein, degreasing said assembled tip and ball with a solvent cleaner, immersing said assembly in a Watts nickel plating bath, subjecting said assembly and bath to an electrical current of between about 5 to about 30 amperes to deposit on the exterior surface of said tip a nickel coating, stopping said current after said coating has reached a maximum thickness ranging between about .4 micron and about .7 micron, removing said assembly from said bath, promptly rinsing said assembly in boiling water to remove any residue of said bath, promptly depositing said assembly in a non-conductive anhydrous ink miscible fluid for storage therein, and removing said assembly from said fluid for the reception of said ink.

8. The method of making a ball point writing assembly which consists of machining a tip blank of an electrochemically active bronze, for-ming ink channels and a socket in said tip blank, preparing a stainless steel writing ball having an electrochemically passive surface, inserting said ball into said socket with a portion thereof exposed, constricting the outer end of said tip beyond the equator of said ball with a space between said ball and said tip of about 1 to 4 microns whereby the ball is held for free universal rotation Within said socket, vapor degreasing said assembly with trichloroethylene, rinsing said assembly in water to remove residual cleaner, immersing said assembly in a Watts nickel plating bath containing a brightener, subjecting said assembly and said bath to an electrical current of about 20 amperes for about 2 minutes to deposit on the exterior surface of said tip a nickel coating having a maximum thickness of about .75 micron at the constricted outer end, removing said assembly from said bath, promptly putting said assembly through several rinses in boiling distilled Water to remove residue of said bath, promptly rinsing and soaking said assembly in methyl alcohol to extract residual water therefrom, promptly transferring said assembly to a storage bath of acetone, and removing said assembly from said storage bath and filling said assembly with an acetone miscible ink.

9. The method of making a ball point writing assembly which consists of forming a socket in a metallic tip having an electrochemically active outer surface, preparing a ceramic Writing ball having an electrochemically passive surface, confining a major portion of said ball within said socket with a portion thereof exposed for free universal rotation, immersing said assembled tip and ball in a plating bath, depositing on said tip a metallic plate ranging between about .25 micron to about .8 micron in thickness, removing said assembly from said bath, cleaning said assembly to remove residue of said bath, and thereafter maintaining said assembly in a non-conductive fluid until it is filled with ink.

10. The method of making a ball type ink dispenser which consists of forming a socket in a metallic tip having an electrochemically active surface, preparinga ball having an electrochemically active surface, coating said ball to render said ball surface electrochemically passive, confining said ball Within said socket with a portion thereof exposed for free universal rotation, degreasing said assembled ball and lip with a cleaner which is non-reactive With said ball coating, immersing said assembly in a plating bath, depositing on said tip a thin metallic plate, removing said assembly from said bath, promptly rinsing said assembly to remove residue of said bath, and maintaining said assembly in a non-conductive ink miscible fluid until said assembly is filled with ink. 

1. THE METHOD OF MAKING A BALL TYPE INK DISPENSING IMPLEMENT WHICH CONSISTS OF FORMING A SOCKET IN A METALLIC TIP HAVING AN ELECTROCHEMICALLY ACTIVE EXTERIOR SURFACE, PREPARING A BALL HAVING AN ELECTROCHEMICALLY PASSIVE SURFACE, CONFINING SAID BALL WITHIN SAID SOCKET WITH A PORTION THEREOF EXPOSED FOR FREE UNIVERSAL ROTATION, IMMERSING SAID ASSEMBLY IN A PLATING BATH, DEPOSITING ON SAID TIP A THIN METALLIC COATING, REMOVING SAID ASSEMBLY FROM SAID BATH, PROMPTLY RINSING SAID ASSEMBLY TO REMOVE RESIDUAL MATERIAL FROM SAID PLATING BATH, AND THEREAFTER MAINTAINING SAID ASSEMBLY IN A NON-CONDUCTIVE FLUID UNTIL READY FOR INKING. 